1. Field of the Invention
The present invention relates to the supporting of underground mine roofs and, more particularly, is directed towards an apparatus for drilling holes in the roof of a mine and for inserting roof bolts into such holes.
2. Description of the Prior Art
In underground mines, the roof is supported by roof bolts which are inserted into holes drilled into the roof strata. An apparatus for drilling holes having a depth substantially greater than the height of the mine passageway in which the apparatus is located is described in U.S. Pat. No. 4,057,115. An apparatus for inserting roof bolts into the drilled holes is described in U.S. Pat. No. 4,003,233.
Although progress has been made in roof bolting apparatus, roof bolting remains one of the most hazardous mining occupations for several reasons. The operator inserting the roof bolt is stationed inby at an area in which the roof is unsupported. It is the operator's task to drill and to insert roof bolts in this unsupported area. Consequently, the operator is exposed to the hazard of having sections of the unsupported roof fall on him. Mine personnel have been injured by flying objects from the exposed rotating drill steel and tools employed to tighten the roof bolts. Workers are also exposed to the risk of being caught on and pulled into the rotating portions of the mining apparatus.
Attempts to develop roof bolters which are capable of remotely installing bolts have been met with limited success even for the simplest case when the bolts are shorter than the height of the mine passageway. Such attempts have resulted in complex and costly systems which suffer from low reliability due to many moving parts and continual readjustment. A need has arisen for an improved roof bolting system which does not suffer from the heretofore mentioned disadvantages.